Arkua™ was nice enough to send a sample of their PIV heatsink, the ARKUA 8568. This is similar in construction to the ARKUA 7528; this features a copper core surrounded by radial aluminum fins. The copper core

is about 20 mm in diameter and 21 mm long. The fit between the core and the surrounding fins is critical to performance.

The base is fairly smooth (the pic looks worse than it is due to moiré patterns), although I could feel some resistance when running a fingernail over its surface. I found that the CPU contact patch was a tad smaller than the PIV:

The red marks outline where the PIV contacts the heatsink.

The top

features a metal clamp that contacts the copper core. The raised portion has a dimple which is directly above the center of the CPU. One side of the heatsink’s locking arms is articulated; to mount the heatsink, you squeeze one side of the top which then moves these arms away from the retaining base. Once you line the locking lugs with the open slots, it then inserts into the holes and locks into place.

Then you move the lever so that it exerts downward pressure on the CPU. Because it is slack when first mounting it, it is fairly easy to mount the arms into the retaining base.

The fan is a fairly quiet 70 mm model from YS Tech, # FD1270155B-1F. It is rated at 32 cfm, 4500 rpm. It only draws 2.3 watts, so using a motherboard fan header is not a problem.

THE TEST

The Arkua was first tested on the CPU Die Simulator which gives results that are unaffected by motherboard influences. The Simulator uses a small die while the PIV uses a heat spreader plate which gives a much larger surface area – the Simulator results are for comparative rankings only. I then tested the Arkua on a Lucky Star P4A845D; ambient temps were measured with a thermocouple placed about 1 inch from the fan’s intake. I used Prime 95 to stress the CPU and MBM Temps are CPU Diode Temps.

The motherboard test is more indicative of what users might see on their own systems.

TEST RESULTS – CPU Simulator

Platform

Die Temp

Ambient Temp

Delta

C/W

Simulator, 76.7 Watts

50.6 C

19.3 C

31.3

0.41

TEST RESULTS – Motherboards

CPU/Motherboard

MBM Temp

Ambient Temp

Delta

PIV @ 1700, Lucky Star, Stock Fan (64 watts)

33 C

19.6 C

13.4

Delta = CPU temp – Ambient Temp
C/W = Delta / CPU Watts

Interpreting C/W: For every watt the CPU radiates, the heatsink will cool the core by the (C/W x watts) plus ambient temp. For example, at an ambient temp of 25 C, a C/W of 0.25 with a CPU radiating 50 watts means that the CPU temp will be 50 x 0.25 = 12.5 C over ambient temp, or 37.5 C. The lower the C/W, the better.

The ARKUA comes in better than Intel’s PIV heatsink (Heatsink Rankings HERE) and ahead of a number of other PIV entries.

CONCLUSIONS

The PIV ARKUA is a competitive PIV heatsink, but I don’t think the performance difference justifes a switch from Intel’s PIV heatsink.